Aphthasol contains 5% amlexanox in an adhesive oral paste. Chemically, amlexanox is 2-amino-7-isopropyl-5-oxo-5H-[1]benzopyrano[2,3-b] pyridine-3-carboxylic acid. It has a molecular formula of C16H14N2O4 and has a molecular weight of 298.30. Amlexanox is odorless, white to yellowish-white crystalline powder. The structural formula is: